1. Field of the Art
This invention relates to a novel process for producing sulfenimides and more particularly to a process for producing sulfenimides a characteristic feature of which is that a mixture comprising a disulfide or a mercaptan and an imide is subjected to an electrolytic oxidation in an organic solvent. The electrolytic oxidation is carried out preferably in the presence of a catalytic amount of a halogenated compound.
A series of the sulfenimides according to the present invention are important compounds for an inhibitor for premature vulcanization of rubber and have a reactivity for serving as a radical uptaking agent or a sulfenylating agent so that such compounds are expected to be used for various purposes.
2. Prior Art
The prior art teaches the producing of sulfenimides in generally the following two ways.
(1) M. Behforouz and J. E. Kerwood in Journal of Organic Chemistry, Vol. 34, P. 51 (1969), disclose producing a sulfenimide by reacting a sulfenyl chloride with an imide in the presence of a tertiary amine.
(2) K. H. Buchel and A. Conte in Chemische Berichte, Vol. 100, P. 1248 (1967) disclose producing a sulfenimide by reacting an N-bromimide with a disulfide.
These conventional processes, however, are accompanied by a number of problems from the viewpoint of the industrial synthesis such as the use of a large quantity of a chemically unstable or expensive reactant in the process and, further, the admixture of a halogenated compound into the product formed, whereby the stability of the product deteriorates in the process.
On the other hand, there has been no report relating to a direct synthesis of sulfenimides in a simple manner from the mixture comprising disulfides or mercaptans which are relatively easily available and imides.